ive tried blue berries, strawberries. They ate the leaves off my tomato plants but not the tomatoes themselves..weird..I've tried halved cabbage right out of the garden, scratch grains..they will eat nothing but flock raiser and grubs.
Something has to be wrong..with the poop pics I've seen here and other sites they have watery squirts..what could they be missing?
First, I've read that tomato stems and leaves are toxic (!!) to ducks, only the fruit is supposed to be edible, so I would start there.
Also I believe the poop usually varies in consistency, depending largely on diet. If you feed them veg with a high water content, it does go more watery. Very dark green veggies like kale can color it as well. My ducks' waste does change a bit day to day, but I've never seen it look as solid as the duck poop I've come across in the wild. Oh the science of poo!
How were your ducks raised? Do you know if they were given treats as ducklings at all? If so, I would revert back to those. In my experience, our Pekins still love the veggies I gave them as wee ones. It's the new fruit, bananas and tomatoes, I've tried to introduce recently that they do not seem to like much.
Lastly, are you able to let them out to free range at all? If so, what are they finding that they like to eat when they're on their own? Mine are partial to fallen oak leaves and the wild grass around here. They loved the miners lettuce that grew in the spring too!
Hope that helps!